Present invention relates to an electron beam lithography apparatus which an electron beam is irradiated to a sample so as to produce a desired lithography pattern on a sample, an electron beam lithography system thereof and an electron beam lithography method used therein.
A functional block diagram of a lithography data generation part in a conventional electron beam lithography apparatus is shown in FIG. 10.
In the conventional electron beam lithography apparatus, the lithography data corresponding to an irradiation unit (coordinates, size, irradiation quantity) generated by an electron beam lithography data generation means 13 are revised by a predetermined electron beam correction means 14, and the electron beam that is designated by the revised lithography data is irradiated to an exposure agent applied on the sample by the electron beam lithography means 16.
There are various kinds of methods to correct the electron beam by the electron beam correction means 14, and a proximity effect correction is applied to them here.
This proximity effect means a phenomenon that a part of an exposure agent having a high ratio of irradiation quantity to an area irradiated with the electron beam, is exposed in excess, because the electron beam that is irradiated on the sample, passes through the layer of the exposure agent on a surface of the sample, and the electron beam scattered at an interior part of the sample passes through the exposure agent of the sample surface again.
In U.S. Pat. No. 5,149,975 and U.S. Pat. No. 5,278,421 corresponding to a Japanese Patent Laid-open No. 3-225816(1991) bulletin relating to the electron beam lithography apparatus, a lithography technique is indicated, whereby an exposure map is obtained in a storage device based on an exposure area density of the pattern to be formed on the sample top without irradiating an electron beam before an actual lithography is done, and the irradiation quantity of the electron beam is corrected to become small relatively in a place where the exposure area density is high, and to become large relatively in a place where the exposure area density is low by an exposure map implementation means 15 shown in FIG. 10 in a real lithography referring to the storage device.
In the prior art mentioned above, in order to perform the most suitable lithography, whenever conditions of mesh size to divide the exposure pattern and number of times to filter are changed, the exposure map is reformed, and an empty lithography operation is performed according to it without irradiating the electron beam so as to be evaluated. Therefore, in order to expose with the lithography data of one pattern ideally, several times of the exposure map implementation and the empty lithography operation becomes necessary.
In the prior art furthermore, as the exposure map is reformed whenever the condition changes, the exposure map before reformed cannot be held. Therefore in order to perform the most suitable lithography again, the same lithography data should be reformed again.
These let throughputs of the electron beam lithography apparatus deteriorate.
In the electron beam lithography apparatus of a mask especially, only one piece of the mask can be exposed for one lithography data and one lithography data cannot be used repeatedly, and there arise a problem that the throughput is deteriorated.
The present invention is provided referring to the problems of such a prior art, and is expected to offer an electron beam lithography apparatus, an electron beam lithography system and a lithography method used therefor to let the throughput improve.
In order to solve the above problem, the electron beam lithography apparatus in the present invention comprises,
a lithography data generation means for generating lithography data to form an exposure pattern on the sample,
an exposure map implementation means for making exposure map of an electron beam from the lithography data,
plurality of lithography data generation parts comprising a electron beam correction means for revising an irradiation quantity of the electron beam irradiated to the sample by referring to the exposure map, and
electron beam lithography means to expose by irradiating the electron beam to the sample based on a value revised with the electron beam correction means.
As plurality of the lithography data generation parts are provided and plural exposure maps based on different conditions and different types can be formed in parallel, the most suitable lithography condition can be analyzed quickly and the above object can be achieved.
As an example of generation condition of the lithography data, mesh size at the time of the exposure map implementation and number of times of smoothing the area density performed between the adjacent meshes are raised.
Moreover, the electron beam lithography apparatus having an output comparing means for comparing an output from the plural several lithography data generation means, can check malfunction of the total control circuit by comparing the output obtained by letting the lithography data generation part operated in the same operation, thereby reliability of the electron beam lithography apparatus can be increased.
Furthermore, the electron beam lithography apparatus has a function to form the exposure map of the second lithography data in parallel during the exposure of the first lithography data.
The electron beam lithography apparatus further has a function to divide and form the exposure map to be exposed with the plural lithography data generation part.
Based on these functions, the implementation of the exposure map is performed in parallel with the plural lithography data generation parts relating to a big exposure pattern which the exposure map to be exposed exceeds a range that can be formed with one lithography data generation part, thereby degradation of the throughput can be prevented.
Moreover, two electron beam lithography apparatus are connected with a data transmission means, and the lithography data formed with the first electron beam lithography apparatus is transmitted to the second electron beam lithography apparatus, thereby the second electron beam lithography apparatus may perform the lithography using the same lithography data in the same way as the first electron beam lithography apparatus.
Moreover, if the electron beam lithography apparatus in the present invention is used for a pattern lithography to a mask, reticle used for an exposure apparatus, the lithography data made once is used repeatedly to expose, and throughput thereof is improved.